To answer your question if I use it or not....I pretty much ignore it. It is a VERY secondary weapon to me. However, it is great to surface when you have already crippled a vessel like most have stated. Keep in mind that running the RFB cannon makes the sim a bit more challenging. Each torpedo is a precious commodity not to be expended lightly and without planning. If the cannon was set up like the ray gun from The Death Star that took out planet Tatooni you would expend your torpedoes like candy because you know you can just surface if you screw up and start blasting with the cannon. I know now that If I do not get at least one torp into the vessel, I will be spending 80 rounds and 45 minutes attemting to sink a vessel with the cannon. Gets really old really fast. So, I make my calculation precise and my aim true concerning my torpedoes. If the vessel is still afloat I then use my cannon.
Just a side note for the RFB users, make sure your merchant is not armed! RFB is now set up that if your sub takes gun fire or cannon fire....kiss your topside crew goodbye. There has been a lot of work concerning this aspect of the game. You will be dragging bloodied bodies below if you surface against an armed merchant! I know, been there and done that. I did a very stupid thing. I did not look to see if a merchant was armed. I surfaced and blamo! I'm writing condolense letters to the next of kin. Not to mention the many holes in my steel tube and hull damage. So, your cannon just became less effective then once thought
